I recommend Librewolf, it’s a lot more privacy-aggressive out of the box, and you can turn that down a little bit if you need, but otherwise it’s just a more trustworthy Firefox fork as far as I’m concerned. It supports Firefox sync as well (which is telling, because Librewolf takes privacy very seriously and isn’t going to provide too many easy opportunities for you to completely compromise it) Like the other person said sync is E2EE and the hosting server has zero-knowledge of any of your unencrypted data. If Librewolf trusts it, I trust it, and I think you can rest assured that with Librewolf, it’s probably never going to be sabotaged either, which as you imply, is not necessarily true with Firefox.

I don’t recall whether they use Firefox’s sync server directly or if they have their own, but either way, like I said, the server has no knowledge of or access to your unencrypted data.

Most of the countries in the western world have spent so long not really being at risk of being at war that we really have no idea how to react to potentially actually being at war. We are so incredibly unprepared in such incredibly profound ways. Imagine being in a war and not having anti-air defenses around your most important strategic nuclear sites and having to rely on troops shooting at incoming aircraft with what I suspect were simply their service weapons, and almost certainly not even dedicated anti-drone weapons. Yes, drones are sort of new, that’s not really an excuse. New things will happen during a war. You have to be able to react quickly to defend your critical assets at a moment’s notice. The fact that we’re still not doing that properly is a perfect demonstration of how far behind the curve we really are.

I hope this changes soon with the sprawling investments being directed towards defense budgets, but I remain unconvinced, will it just result in more hyper-capable, hyper-expensive techno-wonderweapons? It’s the cheap, good-enough, high-supply things that are currently threatening us, and both history and the present seem to tell us it’s usually the cheap, good enough, high-supply things that both win wars and enable effective defense. Spending money seems like it would imply seriousness, but I don’t think we’re actually taking this seriously enough, yet. When you really get serious about war and defense you need to be asking the real questions about what it’s going to take to win, not just throwing money at the problem.

Maybe I’m wrong, maybe they’re just sandbagging and waiting for the right moment to reveal our true defensive preparations, but I know a lot of people in various western militaries, and I honestly don’t think so at all, and neither do they. If we are more prepared than we look, it’s a pretty goddamn well-kept secret.

My old LG SmartTV seems most reliable at playing mkv files but I think mp4 is pretty standard.

It’s very unlikely you are infected by anything unless you were using some crazy settings or addons, or unless you were hit by some extreme 0-day exploit that hasn’t become widespread yet. Firefox does not and normally cannot execute files it downloads automatically nor are videos a likely risk for remote code execution now that we have technologies like data execution prevention built into processors, if you’re attacked by malware it will rely on some other vector or trickery to get you to execute the file. I would expect that your performance issues are unrelated, but you should also check Firefox’s addons and extensions as well as your task manager startup tab to make sure nothing has obviously been installed without your knowledge.

One thing that sticks out at me is the fact that you only mention the file’s “title” and if you haven’t already you should make sure Windows Explorer is set up to ALWAYS show full file extensions, that’s like a basic safety measure that really should be on by default but isn’t, and it’s really mandatory if you’re messing around on the darker parts of the web. You have to know what kind of file extension it is because that affects what Windows is going to do with it, and when it’s supposed to be one thing and Windows is going to do something different with it that’s a huge red flag that it’s malware trying to trick you into running it.

You can upload the file to virustotal if you want to scan it but it doesn’t sound likely that it even ran unless you did something bad by accident.

Ah yes, the famously reliable, safe, and effective Russian submarines, workhorse of the Russian navy. What should they buy next? Some guided missile cruisers? How about an aircraft carrier?